Add signed/unsigned 8-bit and 16-bit Representations

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index a18ff0d274c75e14eac2701a06f5d93e1cf5e8af..3446fcf7c606d8ed0a099b37ddfc31b6889608bd 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -950,8 +950,14 @@ void MacroAssembler::Cvtlsi2sd(XMMRegister dst, const Operand& src) {
 
 void MacroAssembler::Load(Register dst, const Operand& src, Representation r) {
   ASSERT(!r.IsDouble());
-  if (r.IsByte()) {
-    movzxbl(dst, src);
+  if (r.IsInteger8()) {
+    movsxbq(dst, src);
+  } else if (r.IsUInteger8()) {
+    movzxbq(dst, src);

[Benedikt Meurer, 2013/11/07 12:56:05]

We can safely use movzxbl() here, as all 32-bit instructions auto-zero-extend in
long mode. Depending on src and dst this can avoid the REX prefix.

[danno, 2013/11/07 13:19:57]

Done.

+  } else if (r.IsInteger16()) {
+    movsxwq(dst, src);
+  } else if (r.IsUInteger16()) {
+    movzxwq(dst, src);

[Benedikt Meurer, 2013/11/07 12:56:05]

Same.

[danno, 2013/11/07 13:19:57]

Done.

   } else if (r.IsInteger32()) {
     movl(dst, src);
   } else {
@@ -962,8 +968,10 @@ void MacroAssembler::Load(Register dst, const Operand& src, Representation r) {
 
 void MacroAssembler::Store(const Operand& dst, Register src, Representation r) {
   ASSERT(!r.IsDouble());
-  if (r.IsByte()) {
+  if (r.IsInteger8() || r.IsUInteger8()) {
     movb(dst, src);
+  } else if (r.IsInteger16() || r.IsUInteger16()) {
+    movw(dst, src);

[Yang, 2013/11/07 09:32:43]

Can we introduce ASSERTs for is_byte_register() for the 8bit and 16bit case?

Also for ia32 of course.

[danno, 2013/11/07 13:19:57]

This isn't an issue on x64, but I added checks on ia32 for byte registers on
byte access.

[danno, 2013/11/07 13:35:31]

Actually, this isn't necessary here. And in ia32, it is already checked.

   } else if (r.IsInteger32()) {
     movl(dst, src);
   } else {